This invention relates to an apparatus for processing semiconductor wafers or glass photomask plates, and more particularly, to a gas intake assembly for a semiconductor wafer processing system.
In the production of integrated circuits, the semiconductor wafers or substrates from which the integrated circuit chips are cut are processed through multiple steps. The basic material for the substrates on the wafers may be silicon, glass, or ceramic materials of various sorts or other similar materials of very thin wafer-like configuration. This basic substrate is subjected to coating, etching, and cleaning processes and it is extremely important that each processing step is performed with the greatest possible yield allowing a decrease in production costs.
Semiconductor wafers and glass photomask plates have been processed by spinning them about a vertical axis where the wafers or masks are stacked vertically as described in U.S. Pat. No. 3,760,822 with various holding mechanisms such as vacuum chucks. This has led to further disadvantages where the wafer may be only processed on one side at a time without a significantly different processing rate, wherein the topside processes at a much faster rate than that of the underside.
Other processing devices such as described in U.S. Pat. No. 3,970,471, process each wafer individually. Although the wafer is rotated about a horizontal axis, such a device only can process a single wafer at each station and is expensive and time consuming.
To eliminate many of the problems noted above, the assignee of the present invention developed a wafer processing system and set forth and claimed the system in U.S. Pat. No. 4,300,581, titled "Centrifugal Wafer Processor", issued Nov. 17, 1981. The invention set forth therein permits the processing of a plurality of wafers at the same time in a carrier. In accordance with that invention, semiconductor wafers or glass photomask plates are processed by inserting them into the carrier and placing the carrier in a rotor that rotates about a substantially horizontal axis. Various fluids may be applied to the wafers uniformly through spray nozzles while the wafers are being rotated. The spray nozzles are located above and to the side of the carrier permitting the processing to be done at low pressures. After the wafers have been treated with the processing fluid(s), heated nitrogen is provided through one or more nozzles to assist in drying the wafers as the rotor spins them in the carrier.
The present inventors have recognized that heated nitrogen is not the only gas suitable for the drying process. Rather, in certain semiconductor manufacturing processes, ambient gas may be used in the drying process. The present inventors have set forth a unique and economical system for providing such ambient gas in the drying process.